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-rw-r--r--Documentation/core-api/kernel-api.rst6
-rw-r--r--Documentation/driver-api/basics.rst3
-rw-r--r--include/linux/overflow.h38
-rw-r--r--lib/overflow_kunit.c47
4 files changed, 58 insertions, 36 deletions
diff --git a/Documentation/core-api/kernel-api.rst b/Documentation/core-api/kernel-api.rst
index 0793c400d4b0..06f4ab122697 100644
--- a/Documentation/core-api/kernel-api.rst
+++ b/Documentation/core-api/kernel-api.rst
@@ -118,6 +118,12 @@ Text Searching
CRC and Math Functions in Linux
===============================
+Arithmetic Overflow Checking
+----------------------------
+
+.. kernel-doc:: include/linux/overflow.h
+ :internal:
+
CRC Functions
-------------
diff --git a/Documentation/driver-api/basics.rst b/Documentation/driver-api/basics.rst
index 3e2dae954898..4b4d8e28d3be 100644
--- a/Documentation/driver-api/basics.rst
+++ b/Documentation/driver-api/basics.rst
@@ -107,9 +107,6 @@ Kernel utility functions
.. kernel-doc:: kernel/panic.c
:export:
-.. kernel-doc:: include/linux/overflow.h
- :internal:
-
Device Resource Management
--------------------------
diff --git a/include/linux/overflow.h b/include/linux/overflow.h
index 19dfdd74835e..1d3be1a2204c 100644
--- a/include/linux/overflow.h
+++ b/include/linux/overflow.h
@@ -51,8 +51,8 @@ static inline bool __must_check __must_check_overflow(bool overflow)
return unlikely(overflow);
}
-/** check_add_overflow() - Calculate addition with overflow checking
- *
+/**
+ * check_add_overflow() - Calculate addition with overflow checking
* @a: first addend
* @b: second addend
* @d: pointer to store sum
@@ -66,8 +66,8 @@ static inline bool __must_check __must_check_overflow(bool overflow)
#define check_add_overflow(a, b, d) \
__must_check_overflow(__builtin_add_overflow(a, b, d))
-/** check_sub_overflow() - Calculate subtraction with overflow checking
- *
+/**
+ * check_sub_overflow() - Calculate subtraction with overflow checking
* @a: minuend; value to subtract from
* @b: subtrahend; value to subtract from @a
* @d: pointer to store difference
@@ -81,8 +81,8 @@ static inline bool __must_check __must_check_overflow(bool overflow)
#define check_sub_overflow(a, b, d) \
__must_check_overflow(__builtin_sub_overflow(a, b, d))
-/** check_mul_overflow() - Calculate multiplication with overflow checking
- *
+/**
+ * check_mul_overflow() - Calculate multiplication with overflow checking
* @a: first factor
* @b: second factor
* @d: pointer to store product
@@ -96,23 +96,24 @@ static inline bool __must_check __must_check_overflow(bool overflow)
#define check_mul_overflow(a, b, d) \
__must_check_overflow(__builtin_mul_overflow(a, b, d))
-/** check_shl_overflow() - Calculate a left-shifted value and check overflow
- *
+/**
+ * check_shl_overflow() - Calculate a left-shifted value and check overflow
* @a: Value to be shifted
* @s: How many bits left to shift
* @d: Pointer to where to store the result
*
* Computes *@d = (@a << @s)
*
- * Returns true if '*d' cannot hold the result or when 'a << s' doesn't
+ * Returns true if '*@d' cannot hold the result or when '@a << @s' doesn't
* make sense. Example conditions:
- * - 'a << s' causes bits to be lost when stored in *d.
- * - 's' is garbage (e.g. negative) or so large that the result of
- * 'a << s' is guaranteed to be 0.
- * - 'a' is negative.
- * - 'a << s' sets the sign bit, if any, in '*d'.
*
- * '*d' will hold the results of the attempted shift, but is not
+ * - '@a << @s' causes bits to be lost when stored in *@d.
+ * - '@s' is garbage (e.g. negative) or so large that the result of
+ * '@a << @s' is guaranteed to be 0.
+ * - '@a' is negative.
+ * - '@a << @s' sets the sign bit, if any, in '*@d'.
+ *
+ * '*@d' will hold the results of the attempted shift, but is not
* considered "safe for use" if true is returned.
*/
#define check_shl_overflow(a, s, d) __must_check_overflow(({ \
@@ -129,7 +130,6 @@ static inline bool __must_check __must_check_overflow(bool overflow)
/**
* size_mul() - Calculate size_t multiplication with saturation at SIZE_MAX
- *
* @factor1: first factor
* @factor2: second factor
*
@@ -149,7 +149,6 @@ static inline size_t __must_check size_mul(size_t factor1, size_t factor2)
/**
* size_add() - Calculate size_t addition with saturation at SIZE_MAX
- *
* @addend1: first addend
* @addend2: second addend
*
@@ -169,7 +168,6 @@ static inline size_t __must_check size_add(size_t addend1, size_t addend2)
/**
* size_sub() - Calculate size_t subtraction with saturation at SIZE_MAX
- *
* @minuend: value to subtract from
* @subtrahend: value to subtract from @minuend
*
@@ -192,7 +190,6 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend)
/**
* array_size() - Calculate size of 2-dimensional array.
- *
* @a: dimension one
* @b: dimension two
*
@@ -205,7 +202,6 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend)
/**
* array3_size() - Calculate size of 3-dimensional array.
- *
* @a: dimension one
* @b: dimension two
* @c: dimension three
@@ -220,7 +216,6 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend)
/**
* flex_array_size() - Calculate size of a flexible array member
* within an enclosing structure.
- *
* @p: Pointer to the structure.
* @member: Name of the flexible array member.
* @count: Number of elements in the array.
@@ -237,7 +232,6 @@ static inline size_t __must_check size_sub(size_t minuend, size_t subtrahend)
/**
* struct_size() - Calculate size of structure with trailing flexible array.
- *
* @p: Pointer to the structure.
* @member: Name of the array member.
* @count: Number of elements in the array.
diff --git a/lib/overflow_kunit.c b/lib/overflow_kunit.c
index 5369634701fa..b8556a2e7bb1 100644
--- a/lib/overflow_kunit.c
+++ b/lib/overflow_kunit.c
@@ -16,6 +16,34 @@
#include <linux/types.h>
#include <linux/vmalloc.h>
+#define SKIP(cond, reason) do { \
+ if (cond) { \
+ kunit_skip(test, reason); \
+ return; \
+ } \
+} while (0)
+
+/*
+ * Clang 11 and earlier generate unwanted libcalls for signed output
+ * on unsigned input.
+ */
+#if defined(CONFIG_CC_IS_CLANG) && __clang_major__ <= 11
+# define SKIP_SIGN_MISMATCH(t) SKIP(t, "Clang 11 unwanted libcalls")
+#else
+# define SKIP_SIGN_MISMATCH(t) do { } while (0)
+#endif
+
+/*
+ * Clang 13 and earlier generate unwanted libcalls for 64-bit tests on
+ * 32-bit hosts.
+ */
+#if defined(CONFIG_CC_IS_CLANG) && __clang_major__ <= 13 && \
+ BITS_PER_LONG != 64
+# define SKIP_64_ON_32(t) SKIP(t, "Clang 13 unwanted libcalls")
+#else
+# define SKIP_64_ON_32(t) do { } while (0)
+#endif
+
#define DEFINE_TEST_ARRAY_TYPED(t1, t2, t) \
static const struct test_ ## t1 ## _ ## t2 ## __ ## t { \
t1 a; \
@@ -94,7 +122,6 @@ DEFINE_TEST_ARRAY(u32) = {
{-4U, 5U, 1U, -9U, -20U, true, false, true},
};
-#if BITS_PER_LONG == 64
DEFINE_TEST_ARRAY(u64) = {
{0, 0, 0, 0, 0, false, false, false},
{1, 1, 2, 0, 1, false, false, false},
@@ -118,7 +145,6 @@ DEFINE_TEST_ARRAY(u64) = {
false, true, false},
{-15ULL, 10ULL, -5ULL, -25ULL, -150ULL, false, false, true},
};
-#endif
DEFINE_TEST_ARRAY(s8) = {
{0, 0, 0, 0, 0, false, false, false},
@@ -194,7 +220,6 @@ DEFINE_TEST_ARRAY(s32) = {
{S32_MAX, S32_MAX, -2, 0, 1, true, false, true},
};
-#if BITS_PER_LONG == 64
DEFINE_TEST_ARRAY(s64) = {
{0, 0, 0, 0, 0, false, false, false},
@@ -223,7 +248,6 @@ DEFINE_TEST_ARRAY(s64) = {
{-128, -1, -129, -127, 128, false, false, false},
{0, -S64_MAX, -S64_MAX, S64_MAX, 0, false, false, false},
};
-#endif
#define check_one_op(t, fmt, op, sym, a, b, r, of) do { \
int _a_orig = a, _a_bump = a + 1; \
@@ -246,7 +270,7 @@ DEFINE_TEST_ARRAY(s64) = {
#define DEFINE_TEST_FUNC_TYPED(n, t, fmt) \
static void do_test_ ## n(struct kunit *test, const struct test_ ## n *p) \
-{ \
+{ \
check_one_op(t, fmt, add, "+", p->a, p->b, p->sum, p->s_of); \
check_one_op(t, fmt, add, "+", p->b, p->a, p->sum, p->s_of); \
check_one_op(t, fmt, sub, "-", p->a, p->b, p->diff, p->d_of); \
@@ -257,6 +281,12 @@ static void do_test_ ## n(struct kunit *test, const struct test_ ## n *p) \
static void n ## _overflow_test(struct kunit *test) { \
unsigned i; \
\
+ SKIP_64_ON_32(__same_type(t, u64)); \
+ SKIP_64_ON_32(__same_type(t, s64)); \
+ SKIP_SIGN_MISMATCH(__same_type(n ## _tests[0].a, u32) && \
+ __same_type(n ## _tests[0].b, u32) && \
+ __same_type(n ## _tests[0].sum, int)); \
+ \
for (i = 0; i < ARRAY_SIZE(n ## _tests); ++i) \
do_test_ ## n(test, &n ## _tests[i]); \
kunit_info(test, "%zu %s arithmetic tests finished\n", \
@@ -272,10 +302,8 @@ DEFINE_TEST_FUNC(u16, "%d");
DEFINE_TEST_FUNC(s16, "%d");
DEFINE_TEST_FUNC(u32, "%u");
DEFINE_TEST_FUNC(s32, "%d");
-#if BITS_PER_LONG == 64
DEFINE_TEST_FUNC(u64, "%llu");
DEFINE_TEST_FUNC(s64, "%lld");
-#endif
DEFINE_TEST_ARRAY_TYPED(u32, u32, u8) = {
{0, 0, 0, 0, 0, false, false, false},
@@ -715,13 +743,10 @@ static struct kunit_case overflow_test_cases[] = {
KUNIT_CASE(s16_s16__s16_overflow_test),
KUNIT_CASE(u32_u32__u32_overflow_test),
KUNIT_CASE(s32_s32__s32_overflow_test),
-/* Clang 13 and earlier generate unwanted libcalls on 32-bit. */
-#if BITS_PER_LONG == 64
KUNIT_CASE(u64_u64__u64_overflow_test),
KUNIT_CASE(s64_s64__s64_overflow_test),
-#endif
- KUNIT_CASE(u32_u32__u8_overflow_test),
KUNIT_CASE(u32_u32__int_overflow_test),
+ KUNIT_CASE(u32_u32__u8_overflow_test),
KUNIT_CASE(u8_u8__int_overflow_test),
KUNIT_CASE(int_int__u8_overflow_test),
KUNIT_CASE(shift_sane_test),